The invention relates to an automated bag filling machine for individually opening, filling, closing, and separating zipper-lock, reclosable plastic bags laterally interconnected in a chain and, more particularily, means for assuring proper alignment of each bag before the various work stations of the machine.
Prior to the instant invention, mechanisms for automatically feeding, loading, and sealing plastic bags have been devised. Prior art arrangements of this type are shown, for example, in U.S. Pat. No. 3,477,196 and U.S. Pat. No. 3,952,480. Both of these patents relate to mechanisms for conducting in seriatim a series of plastic bags, originally opened at one mouth end and connected together in a bag chain, to a loading station where the bags are individually loaded with material deposited through their open mouth ends and then to a closing station where the mouth ends of the bags are individually closed by heat sealing means.
No automatic bag loading mechanism has heretofore been devised to handle zipper lock plastic bags of the type disclosed, for example, in U.S. Pat. No. 3,198,228 and presently manufactured by Minigrip, Inc., of Orangeburg, N.Y. This form of bag has closed bottom end and side edges and a reclosable upper end mouth having interlocking fastener strip rib and groove profiles running across inner facing surfaces of the mouth. The nature of manufacture and operation of the reclosable plastic bags present altogether different handling problems than those presented by bags arranged for heat seal closing. For instance, reclosable zipper lock plastic bags are typically closed at their mouth ends during the manufacture process in order to allow proper interfitting of the rib and groove members and exit the manufacturing site in that closed condition. The bag mouths must be opened at a loading site to permit filling and then closed again for packaging. Heretofore known automatic bag loading devices, such as disclosed in U.S. Pat. No. 3,477,196 and U.S. Pat. No. 3,952,480,are not capable of feeding, filling, and sealing reclosable zipper lock plastic bags, since the bag handling mechanisms of these devices are not conducive or adaptable to the unique characteristics of the reclosable bags. Accordingly, it has been necessary to provide manual loading of reclosable lock bags, making such a loading operation very expensive in terms of labor costs and requiring much time since the loader must first manually open the initially closed bag, deposit fill material into the bag, manually interlock the bag mouth fastener strip profiles, and finally transfer the loaded bag to a packaging station.
A mechanism for automatically filling reclosable plastic bags of the zipper-lock type is disclosed herein. The subject invention concerns means by which each bag of a laterally interconnected chain of bags is assured of proper alignment or registration before the various work stations of the filling mechanism, despite tolerance variations in bag size, slippage in drive devices, and/or slack development in the chain.